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Tesla shares 48V architecture with other automakers

electrek.co

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Re: Tesla shares 48V architecture with other automakers

#191

Post by NelsonMinar »

jmrm wrote: post #141

>48V architecture also potentially improves overall electrical efficiency for reasons that I am not sufficiently qualified to explain beyond a kindergarten level This is double bad in a green energy and EV website: On one hand, they admit they don't now why that happens, but on the other hand, they also didn't research just a bit more on that, and that's bad journalism. Most of the comment threads in this HN post are…

I wish the article had more info too. But I appreciate the author acknowledging the limit of their work and not trying to bullshit or skip over it.

I read Electrek daily and find it very useful. They cover a broad range of topic with more insight and voice than the usual crappy blogs that just rewrite press releases or someone else's articles. I particularly like the articles (like this one) that have "Electrek's Take". The Weird Alibaba EV articles are good fun too: https://electrek.co/guides/alibaba/

Re: Tesla shares 48V architecture with other automakers

#192

Post by 1970-01-01 »

jmrm wrote: post #141

>48V architecture also potentially improves overall electrical efficiency for reasons that I am not sufficiently qualified to explain beyond a kindergarten level This is double bad in a green energy and EV website: On one hand, they admit they don't now why that happens, but on the other hand, they also didn't research just a bit more on that, and that's bad journalism. Most of the comment threads in this HN post are…

>potentially improves overall electrical efficiency

Looks like he understood it the entire time :)

Re: Tesla shares 48V architecture with other automakers

#193

Post by arcticbull »

ipaddr wrote: post #173
wnevets wrote: post #148

Earlier quoted context omitted.

I don't know if I would call a self proclaimed content marketer a Journalist.

He said "Journalism". A non-journalist can produce material that can be considered journalism. A student can teach. A homemaker can even write working code. The labels we give to others to divide us

> The labels we give to others to divide us

Labels are an optimisation, an imperfect shortcut. They are a way we represent ourselves to others. If you don't tell me you're an engineer, I have to ask a ton of questions to assess your area of competence and skill. If you tell me you're an engineer I can save minutes or hours by putting you in a rough box. If that box is unnecessarily constraining it'll become clear as we spend more time together.

Re: Tesla shares 48V architecture with other automakers

#194

Post by arcticbull »

Moto7451 wrote: post #189

Audi also has a 48v architecture in use for mild hybrids like my SQ5. This is an older article but explains it well https://www.greencarcongress.com/2017/06/20170602-audi.html My 2021 is fully 48v except for an inverter for necessary 12v circuits (like cigarette outlets and the jumper pins) and a small motorcycle battery that is used for minimal 12v functionality. The mild hybrid battery is under the rear seats and s…

Most automotive parts are 12V so that just means due to economy of scale, 48V parts are more expensive. They are trying to reduce their cost basis by getting everyone to move over to a common, more efficient voltage spec. This is good industry advocacy.

Re: Tesla shares 48V architecture with other automakers

#195

Post by jacquesm »

IgorPartola wrote: post #190
jacquesm wrote: post #142

Earlier quoted context omitted.

Indeed, I'm aware of only one recorded death by electrocution at 48V, iirc it was a Swiss radio amateur that had done a bunch of gardening sat down sweaty in a metallic chair and reached for the one switch of his set. Probably there were other contributory causes as well, I've been zapped multiple times from much higher voltage sources (that could have easily supplied the power required) and lived. I can't find a ref…

I assume if you didn’t live from those zaps you wouldn’t be here making this comment.

Haha, fair point, yes, indeed. The most clear form of survivorship bias, thank you for pointing it out.

Re: Tesla shares 48V architecture with other automakers

#196

Post by GuB-42 »

sitkack wrote: post #2

TIL that 42V fizzled out https://en.wikipedia.org/wiki/42-volt_electrical_system I welcome the move to 48V, as one gets lots of cross over synergies from the 48V telco standard. https://www.servertech.com/blog/48vdc-power-and-the-backbone... https://www.st.com/content/dam/AME/2019/developers-conferenc... https://www.maximintegrated.com/content/dam/files/products/p... https://www.infineon.com/cms/en/applications/infor…

Are you telling us that 42 wasn't the answer after all?

Re: Tesla shares 48V architecture with other automakers

#197

Post by eqvinox »

Moto7451 wrote: post #184
numpad0 wrote: post #105

Earlier quoted context omitted.

Automotive Ethernet is not 8P8C...that's not how they do it at all

Some cars even use optical networking between the front and rear of the car. I think a bit of that has gone away now that you don’t need a DVD full of map data in its own module in the trunk.

You don't need it for the DVD anymore, now it's the zillions of cameras instead. The IEEE recently standardized automotive (= single pair) multi-gigabit ethernet (2.5/5/10GE) in 802.3ch…

Re: Tesla shares 48V architecture with other automakers

#198

Post by [deleted] »

jrockway wrote: post #179
jnsaff2 wrote: post #83

The "expert" in the article got it wrong. The relationship between the voltage and the losses in the wires is not proportional. They are squared. Going from 12V to 48V is not a saving of 4x rather 16x. For some applications you could also consider Power over Ethernet in the car, get both shielded comms and power. Or can and power over twisted pair.

> Or can and power over twisted pair. I was reading an anti-Musk subreddit over on Reddit and I think the cybertruck is doing this? They were mad that the cybertruck uses 48V and Ethernet cables, but to me, that seems perfect for CAN and power. We already use 48V (or similar) for PoE, and CAN needs a twisted pair... so why not buy that off the shelf instead of using a custom wiring harness? I don't think the cybertru…

[deleted]

Re: Tesla shares 48V architecture with other automakers

#199

Post by tgsovlerkhgsel »

mcguire wrote: post #81
myself248 wrote: post #60

Earlier quoted context omitted.

Hi, automotive electrical is my job. There's quite a bit of very thick wiring in a car, not just the starter wire, but boring stuff like audio amplifiers, rear window defrosters, power seat motors. Those things don't draw a ton of power, like maybe just a few hundred watts, but at 12 volts even modest powers require extraordinarily thick wires, especially when you account for bundle derating. This requires large term…

The rumor I heard was that the higher voltage resulted in lower switch lifetimes. Any truth to that?

Would there actually be switches switching 12 or 48V in a modern car, especially a Tesla? I'd expect the switches to only switch signal voltage/current, and power electronics (MOSFET? no idea, not an electrical engineer) switching the actual loads.

Re: Tesla shares 48V architecture with other automakers

#200

Post by eqvinox »

contingencies wrote: post #84
jnsaff2 wrote: post #83

The "expert" in the article got it wrong. The relationship between the voltage and the losses in the wires is not proportional. They are squared. Going from 12V to 48V is not a saving of 4x rather 16x. For some applications you could also consider Power over Ethernet in the car, get both shielded comms and power. Or can and power over twisted pair.

The great thing about PoE standards is there's so many to choose from. https://en.wikipedia.org/wiki/Power_over_Ethernet#Standards_... Honestly, ethernet introduces a degree of non-determinism with respect to time in the link layer, plus increased bringup times, a potentially more costly core switching fabric, and the need for critical revision of latency assumptions on any potentially safety-related control concerns…

> The great thing about PoE standards is there's so many to choose from.

There is nothing to choose there. They're supersets of each other with increasing power budget, each including the previous revision as lower power classes.

(and PoDL is not PoE; PoDL is for automotive ethernet, which has nothing to do with the RJ45 you see everywhere on consumer/business IT. You never choose between PoDL and PoE, the choice is made when you decided between Xbase-T vs. Xbase-T1.)

> ethernet introduces a degree of non-determinism with respect to time in the link layer

That's what TSN is for, cf. sibling comment.

> plus increased bringup times

That's generally an IP problem, not Ethernet.

> a potentially more costly core switching fabric

I guess it depends on your application; a TSN-capable 8-port automotive ethernet switch is $10: https://www.digikey.com/en/products/detail/microchip-technol... (non-TSN non-automotive is cheaper…)

> heterogeneous infrastructure costs

Automotive ethernet is supposed to replace CAN and the various heterogeneous higher-speed interfaces that were added to deal with higher bandwidth requirements with a homogeneous ethernet world :)

(Source: I work on some software remotely related to some of this shit. Which does mean I'm biased since I don't know whether it will in fact proliferate, I just make it work ;)

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